The present invention is generally related to an appliance for drying articles, and, more particularly, the present invention is related to a dryer using microprocessor-based control for automatically shutting off the dryer.
It is known that the optimum drying time for clothes varies greatly as a function of the fabric type and size of the load. For example, it is generally desirable to dry at a relatively high temperature so as to minimize the drying time, but some fabric types are damaged by hot temperatures. Also, different types of fabrics have different water storage capacities and different water removal rates. Since the drying results provided by known dryer control techniques are believed to be somewhat unpredictable, there is a need for a clothes dryer that can statistically and probabilistically estimate the time when the articles will reach a desired moisture content or degree of dryness with a high degree of accuracy, regardless of the specific characteristics of the articles and various dry-cycle parameters selectable by the user. This ability would facilitate any further clothes processing, such as execution of a sanitize cycle for eliminating microorganisms after executing a dry cycle.
It would be further desirable to provide a dryer that is able to use noise-filtering techniques suited to reduce the noise level of a sensor signal indicative of the moisture content of the articles in order to further enhance the accuracy of dry-cycle time estimates. It would be also desirable to provide an initial estimate of the stop time of a dry cycle to be executed based on historical data collected from a previously executed cycle. Additionally, it would be desirable to provide consistent relationships for any such initial stop time estimate to account for the specific characteristics of the articles and the dry-cycle parameters selectable by the user. Moreover, it would be desirable to automatically adjust any initial time estimate as the respective cycle is being executed based on algorithms or logic designed to account for the actual dry-cycle conditions. Another desirable feature in a dryer would be to display to the user information regarding the time remaining for executing any cycle being selected by the user, while avoiding jumps in the time display that could be based on a respective functional relationship of the noise-reduced signal, and the elapsed time signal, relative to one or more characteristics of the articles and one or more desired values of predetermined dry-cycle parameters selectable by a respective user of the dryer. The initial estimate of the stop time is superceded by the stop time estimated as the cycle is being executed.